2025-07-11 パシフィック・ノースウェスト国立研究所（PNNL）
＜関連情報＞
- https://www.pnnl.gov/publications/drivers-impacts-sediment-deposition-amazonian-floodplains
- https://www.nature.com/articles/s41467-025-57495-1
アマゾンの氾濫原における土砂堆積の要因と影響 Drivers and impacts of sediment deposition in Amazonian floodplains
Dongyu Feng,Zeli Tan,Sebastien Pinel,Donghui Xu,João Henrique Fernandes Amaral,Alice César Fassoni-Andrade,Marie-Paule Bonnet & Gautam Bisht
Nature Communications Published:02 April 2025
DOI:https://doi.org/10.1038/s41467-025-57495-1
Abstract
The Amazon River carries enormous amounts of sediment from the Andes mountains, much of which is deposited in its floodplains. However, accurate quantification of the sediment sink at fine spatiotemporal scales is still challenging. Here, we present a high-resolution hydrodynamic-sediment model to simulate sediment deposition in a representative Amazon/Solimões floodplain. The process is found to be jointly driven by inundation, suspended sediment concentration in the Amazon River, and floodplain hydrodynamics and only weakly correlated with inundation level. By upscaling the sediment deposition rate (1.33 ± 0.24 kg m−2 yr−1), we estimate the trapping of 77.3 ± 13.9 Mt (or 6.1 ± 1%) of the Amazon River sediment by the Amazon/Solimões floodplains every year. Widespread deforestation would reduce the trapping efficiency of the floodplains over time, exacerbating downstream river aggradation. Additionally, we show that the deposition of sediment-associated organic carbon plays a minor role in fueling carbon dioxide and methane emissions in the Amazon.
